U.S. patent application number 16/886282 was filed with the patent office on 2021-12-02 for artificial muscles comprising an electrode pair and artificial muscle assemblies including same.
This patent application is currently assigned to Toyota Motor Engineering & Manufacturing North America, Inc.. The applicant listed for this patent is Toyota Motor Engineering & Manufacturing North America, Inc.. Invention is credited to Madison B. Emmett, Shardul S. Panwar, Michael P. Rowe.
Application Number | 20210370499 16/886282 |
Document ID | / |
Family ID | 1000004900225 |
Filed Date | 2021-12-02 |
United States Patent
Application |
20210370499 |
Kind Code |
A1 |
Rowe; Michael P. ; et
al. |
December 2, 2021 |
ARTIFICIAL MUSCLES COMPRISING AN ELECTRODE PAIR AND ARTIFICIAL
MUSCLE ASSEMBLIES INCLUDING SAME
Abstract
An artificial muscle that includes a housing having an electrode
region and an expandable fluid region and an electrode pair
positioned in the electrode region, the electrode pair having a
first electrode fixed to a first surface of the housing and a
second electrode fixed to a second surface of the housing. The
first and second electrodes each have two or more tab portions and
two or more bridge portions. Each of the two or more bridge
portions interconnects adjacent tab portions and at least one of
the first and second electrodes includes a central opening
positioned between the two or more tab portions and encircling the
expandable fluid region. A dielectric fluid is housed within the
housing and the electrode pair is actuatable between a non-actuated
and an actuated state such that actuation from the non-actuated to
actuated state directs the dielectric fluid into the expandable
fluid region.
Inventors: |
Rowe; Michael P.; (Pinckney,
MI) ; Panwar; Shardul S.; (Ann Arbor, MI) ;
Emmett; Madison B.; (Ann Arbor, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Toyota Motor Engineering & Manufacturing North America,
Inc. |
Plano |
TX |
US |
|
|
Assignee: |
Toyota Motor Engineering &
Manufacturing North America, Inc.
Plano
TX
|
Family ID: |
1000004900225 |
Appl. No.: |
16/886282 |
Filed: |
May 28, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F15B 7/00 20130101; F15B
15/10 20130101 |
International
Class: |
B25J 9/10 20060101
B25J009/10; B25J 9/14 20060101 B25J009/14; F03G 7/06 20060101
F03G007/06; H02N 1/00 20060101 H02N001/00 |
Claims
1. An artificial muscle comprising: a housing comprising an
electrode region and an expandable fluid region; an electrode pair
positioned in the electrode region of the housing, the electrode
pair comprising a first electrode fixed to a first surface of the
housing and a second electrode fixed to a second surface of the
housing, wherein: the first electrode and the second electrode each
comprise two or more tab portions and two or more bridge portions,
wherein: each of the two or more bridge portions interconnects
adjacent tab portions; and at least one of the first electrode and
the second electrode comprises a central opening positioned between
the two or more tab portions and encircling the expandable fluid
region; and a dielectric fluid housed within the housing; wherein
the electrode pair is actuatable between a non-actuated state and
an actuated state such that actuation from the non-actuated state
to the actuated state directs the dielectric fluid into the
expandable fluid region.
2. The artificial muscle of claim 1, wherein the housing comprises
a first film layer and a second film layer partially sealed to one
another to define a sealed portion of the housing, the housing
further comprising an unsealed portion surrounded by the sealed
portion, wherein the electrode region and the expandable fluid
region of the housing are disposed in the unsealed portion.
3. The artificial muscle of claim 2, wherein the first film layer
and the second film layer are each biaxially oriented polypropylene
films.
4. The artificial muscle of claim 1, further comprising a first
electrical insulator layer fixed to an inner surface of the first
electrode opposite the first surface of the housing and a second
electrical insulator layer fixed to an inner surface of the second
electrode opposite the second surface of the housing, wherein the
first electrical insulator layer and the second electrical
insulator layer each includes an adhesive surface and an opposite
non-sealable surface.
5. The artificial muscle of claim 1, wherein the first electrode
and the second electrode are each an aluminum-coated polyester
electrode.
6. The artificial muscle of claim 1, wherein the first electrode
and the second electrode each includes two pairs of tab portions
and two pairs of bridge portions, each bridge portion
interconnecting adjacent a pair of adjacent tab portions, each tab
portion diametrically opposing an opposite tab portion.
7. The artificial muscle of claim 1, wherein the two or more tab
portions each have a tab length and the two or more bridge portions
each have a bridge length extending radially from the central
opening, the bridge length being 20% to 50% of the tab length.
8. The artificial muscle of claim 1, wherein each of the first
electrode and the second electrode comprise a central opening
positioned between the two or more tab portions and encircling the
expandable fluid region, the central openings being coaxially
aligned with one another.
9. The artificial muscle of claim 1, wherein: when the electrode
pair is in the non-actuated state, the first electrode and the
second electrode are non-parallel to one another; and when the
electrode pair is in the actuated state, the first electrode and
the second electrode are parallel to one another, such that the
first electrode and the second electrode are configured to zipper
toward one another and toward the central opening when actuated
from the non-actuated state to the actuated state.
10. An artificial muscle assembly comprising: a plurality of
artificial muscles, each artificial muscle comprising: a housing
comprising an electrode region and an expandable fluid region; an
electrode pair positioned in the electrode region of the housing,
the electrode pair comprising a first electrode fixed to a first
surface of the housing and a second electrode fixed to a second
surface of the housing, wherein: the first electrode and the second
electrode each comprise two or more tab portions and two or more
bridge portions, wherein: each of the two or more bridge portions
interconnects adjacent tab portions; and at least one of the first
electrode and the second electrode comprise a central opening
positioned between the two or more tab portions and encircling the
expandable fluid region; and a dielectric fluid housed within the
housing, wherein the plurality of artificial muscles is arranged in
a stack such that the expandable fluid region of each artificial
muscle is coaxially aligned with one another; and wherein the
electrode pair is actuatable between a non-actuated state and an
actuated state such that actuation from the non-actuated state to
the actuated state directs the dielectric fluid into the expandable
fluid region.
11. The artificial muscle assembly of claim 10, wherein the
plurality of artificial muscles are electrically coupled to one
another and configured to simultaneously actuate between the
non-actuated state and the actuated state.
12. The artificial muscle assembly of claim 10, further comprising:
a first electrical insulator layer fixed to an inner surface of the
first electrode opposite the first surface of the housing and a
second electrical insulator layer fixed to an inner surface of the
second electrode opposite the second surface of the housing,
wherein the first electrical insulator layer and the second
electrical insulator layer each includes an adhesive surface and an
opposite non-sealable surface.
13. The artificial muscle of claim 10, wherein the first electrode
and the second electrode each includes two pairs of tab portions
and two pairs of bridge portions, each bridge portion
interconnecting a pair of adjacent tab portions, each tab portion
diametrically opposing an opposite tab portion.
14. The artificial muscle of claim 10, wherein each of the first
electrode and the second electrode comprise a central opening
positioned between the two or more tab portions and encircling the
expandable fluid region, the central openings being coaxially
aligned with one another.
15. The artificial muscle of claim 10, wherein: when the electrode
pair is in the non-actuated state, the first electrode and the
second electrode are non-parallel to one another; and when the
electrode pair is in the actuated state, the first electrode and
the second electrode are parallel to one another, such that the
first electrode and the second electrode are configured to zipper
toward one another and toward the central opening when actuated
from the non-actuated state to the actuated state.
16. A method for actuating an artificial muscle assembly, the
method comprising: generating a voltage using a power supply
electrically coupled to an electrode pair of an artificial muscle,
the artificial muscle comprising a housing with an electrode region
and an expandable fluid region, wherein: the electrode pair is
positioned in the electrode region of the housing; the electrode
pair comprises a first electrode fixed to a first surface of the
housing and a second electrode fixed to opposing second surface of
the housing; the first electrode and the second electrode each
comprise two or more tab portions and two or more bridge portions,
wherein: each of the two or more bridge portions interconnects
adjacent tab portions; and at least one of the first electrode and
the second electrode comprises a central opening positioned between
the two or more tab portions encircling the expandable fluid
region; and a dielectric fluid is housed within the housing, and
applying the voltage to the electrode pair of the artificial
muscle, thereby actuating the electrode pair from a non-actuated
state and an actuated state such that the dielectric fluid is
directed into the expandable fluid region of the housing and
expands the expandable fluid region.
17. The method of claim 16, wherein the housing comprises a first
film layer and a second film layer, and partially heat sealing the
first film layer and the second to one another to define a sealed
portion of the housing, the housing further comprising an unsealed
portion surrounded by the sealed portion, wherein the electrode
region and the expandable fluid region of the housing are disposed
in the unsealed portion.
18. The method of claim 16, wherein a controller is communicatively
coupled to the electrode pair, and the controller directing a
voltage from the power supply across the first electrode and the
second electrode to actuate the artificial muscle from the
non-actuated state to the actuated state.
19. The method of claim 16, wherein the artificial muscle is one of
a plurality of artificial muscles arranged in a stack such that the
expandable fluid region of each artificial muscle is coaxially
aligned with one another.
20. The method of claim 16, wherein expanding the expandable fluid
region produces a force greater than 4 Nmm per cm.sup.3 of actuator
volume.
Description
TECHNICAL FIELD
[0001] The present specification generally relates to apparatus and
methods for focused inflation on at least one surface of a device,
and, more specifically, apparatus and methods for utilizing an
electrode pair to direct a fluid to inflate the device.
BACKGROUND
[0002] Current robotic technologies rely on rigid components, such
as servomotors to perform tasks, often in a structured environment.
This rigidity presents limitations in many robotic applications,
caused, at least in part, by the weight-to-power ratio of
servomotors and other rigid robotics devices. The field of soft
robotics improves on these limitations by using artificial muscles
and other soft actuators. Artificial muscles attempt to mimic the
versatility, performance, and reliability of a biological muscle.
Some artificial muscles rely on fluidic actuators, but fluidic
actuators require a supply of pressurized gas or liquid, and fluid
transport must occur through systems of channels and tubes,
limiting the speed and efficiency of the artificial muscles. Other
artificial muscles use thermally activated polymer fibers, but
these are difficult to control and operate at low efficiencies.
[0003] One particular artificial muscle design is described in the
paper titled Hydraulically amplified self-healing electrostatic
actuators with muscle-like performance by E. Acome, S. K. Mitchell,
T. G. Morrissey, M. B. Emmett, C. Benjamin, M. King, M. Radakovitz,
and C. Keplinger (Science 5 Jan. 2018: Vol. 359, Issue 6371, pp.
61-65). These hydraulically amplified self-healing electrostatic
(HASEL) actuators use electrostatic and hydraulic forces to achieve
a variety of actuation modes. However, HASEL actuator artificial
muscles have a limited actuator power per unit volume.
[0004] Accordingly, a need exists for improved artificial muscles
with increased actuator power per unit volume.
SUMMARY
[0005] In one embodiment, an artificial muscle includes a housing
having an electrode region and an expandable fluid region and an
electrode pair positioned in the electrode region of the housing,
the electrode pair having a first electrode fixed to a first
surface of the housing and a second electrode fixed to a second
surface of the housing. The first electrode and the second
electrode each have two or more tab portions and two or more bridge
portions. Each of the two or more bridge portions interconnects
adjacent tab portions and at least one of the first electrode and
the second electrode includes a central opening positioned between
the two or more tab portions and encircling the expandable fluid
region. A dielectric fluid is housed within the housing and the
electrode pair is actuatable between a non-actuated state and an
actuated state such that actuation from the non-actuated state to
the actuated state directs the dielectric fluid into the expandable
fluid region.
[0006] In another embodiment, an artificial muscle assembly
includes a plurality of artificial muscles, each artificial muscle
having a housing with an electrode region and an expandable fluid
region and an electrode pair positioned in the electrode region of
the housing, the electrode pair including a first electrode fixed
to a first surface of the housing and a second electrode fixed to a
second surface of the housing. The first electrode and the second
electrode each include two or more tab portions and two or more
bridge portions. Each of the two or more bridge portions
interconnects adjacent tab portions and at least one of the first
electrode and the second electrode include a central opening
positioned between the two or more tab portions and encircling the
expandable fluid region. A dielectric fluid housed within the
housing, the plurality of artificial muscles is arranged in a stack
such that the expandable fluid region of each artificial muscle is
coaxially aligned with one another, and the electrode pair is
actuatable between a non-actuated state and an actuated state such
that actuation from the non-actuated state to the actuated state
directs the dielectric fluid into the expandable fluid region.
[0007] In yet another embodiment, a method for actuating an
artificial muscle assembly includes generating a voltage using a
power supply electrically coupled to an electrode pair of an
artificial muscle, the artificial muscle having a housing with an
electrode region and an expandable fluid region. The electrode pair
is positioned in the electrode region of the housing. The electrode
pair includes a first electrode fixed to a first surface of the
housing and a second electrode fixed to opposing second surface of
the housing. The first electrode and the second electrode each
include two or more tab portions and two or more bridge portions.
Each of the two or more bridge portions interconnects adjacent tab
portions and at least one of the first electrode and the second
electrode has a central opening positioned between the two or more
tab portions encircling the expandable fluid region. A dielectric
fluid is housed within the housing. The method further includes
applying the voltage to the electrode pair of the artificial
muscle, thereby actuating the electrode pair from a non-actuated
state and an actuated state such that the dielectric fluid is
directed into the expandable fluid region of the housing and
expands the expandable fluid region.
[0008] These and additional features provided by the embodiments
described herein will be more fully understood in view of the
following detailed description, in conjunction with the
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The embodiments set forth in the drawings are illustrative
and exemplary in nature and not intended to limit the subject
matter defined by the claims. The following detailed description of
the illustrative embodiments can be understood when read in
conjunction with the following drawings, where like structure is
indicated with like reference numerals and in which:
[0010] FIG. 1 schematically depicts an exploded view of an
illustrative artificial muscle, according to one or more
embodiments shown and described herein;
[0011] FIG. 2 schematically depicts a top view of the artificial
muscle of FIG. 1, according to one or more embodiments shown and
described herein;
[0012] FIG. 3 schematically depicts a cross-sectional view of the
artificial muscle of FIG. 1 taken along line 3-3 in FIG. 2 in a
non-actuated state, according to one or more embodiments shown and
described herein;
[0013] FIG. 4 schematically depicts a cross-sectional view of the
artificial muscle of FIG. 3 in an actuated state, according to one
or more embodiments shown and described herein;
[0014] FIG. 5 schematically depicts a cross-sectional view of an
illustrative artificial muscle in a non-actuated state, according
to one or more embodiments shown and described herein;
[0015] FIG. 6 schematically depicts a cross-sectional view of the
artificial muscle of FIG. 5 in an actuated state, according to one
or more embodiments shown and described herein;
[0016] FIG. 7 schematically depicts an artificial muscle assembly
including a plurality of the artificial muscles of FIG. 1,
according to one or more embodiments shown and described herein;
and
[0017] FIG. 8 schematically depicts an actuation system for
operating the artificial muscle of FIG. 1, according to one or more
embodiments shown and described herein.
DETAILED DESCRIPTION
[0018] Embodiments described herein are directed to artificial
muscles and artificial muscle assemblies that include a plurality
of artificial muscles. The artificial muscles described herein are
actuatable to selectively raise and lower a region of the
artificial muscles to provide a selective, on demand inflated
expandable fluid region. The artificial muscles include a housing
and an electrode pair. A dielectric fluid is housed within the
housing, and the housing includes an electrode region and an
expandable fluid region, where the electrode pair is positioned in
the electrode region. The electrode pair includes a first electrode
fixed to a first surface of the housing and a second electrode
fixed to a second surface of the housing. The electrode pair is
actuatable between a non-actuated state and an actuated state such
that actuation from the non-actuated state to the actuated state
directs the dielectric fluid into the expandable fluid region. This
expands the expandable fluid region, raising a portion of the
artificial muscle on demand. Further, the first electrode and the
second electrode each includes two or more tab portions and two or
more bridge portions interconnecting adjacent tab portions, and at
least one of the first electrode and the second electrode includes
a central opening positioned between the tab portions and encircles
the expandable fluid region. The tab portion and bridge portion
design of the electrode pair facilitates a zippering actuation
motion to increase the force per unit volume achievable by
actuation of the artificial muscle. Various embodiments of the
artificial muscle and the operation of the artificial muscle are
described in more detail herein. Whenever possible, the same
reference numerals will be used throughout the drawings to refer to
the same or like parts.
[0019] Referring now to FIGS. 1 and 2, an artificial muscle 100 is
shown. The artificial muscle 100 includes a housing 102, an
electrode pair 104, including a first electrode 106 and a second
electrode 108, fixed to opposite surfaces of the housing 102, a
first electrical insulator layer 110 fixed to the first electrode
106, and a second electrical insulator layer 112 fixed to the
second electrode 108. In some embodiments, the housing 102 is a
one-piece monolithic layer including a pair of opposite inner
surfaces, such as a first inner surface 114 and a second inner
surface 116, and a pair of opposite outer surfaces, such as a first
outer surface 118 and a second outer surface 120. In some
embodiments, the first inner surface 114 and the second inner
surface 116 of the housing 102 are heat-sealable. In other
embodiments, the housing 102 may be a pair of individually
fabricated film layers, such as a first film layer 122 and a second
film layer 124. Thus, the first film layer 122 includes the first
inner surface 114 and the first outer surface 118, and the second
film layer 124 includes the second inner surface 116 and the second
outer surface 120.
[0020] Throughout the ensuing description, reference may be made to
the housing 102 including the first film layer 122 and the second
film layer 124, as opposed to the one-piece housing. It should be
understood that either arrangement is contemplated. In some
embodiments, the first film layer 122 and the second film layer 124
generally include the same structure and composition. For example,
in some embodiments, the first film layer 122 and the second film
layer 124 each comprises biaxially oriented polypropylene.
[0021] The first electrode 106 and the second electrode 108 are
each positioned between the first film layer 122 and the second
film layer 124. In some embodiments, the first electrode 106 and
the second electrode 108 are each aluminum-coated polyester such
as, for example, Mylar.RTM.. In addition, one of the first
electrode 106 and the second electrode 108 is a negatively charged
electrode and the other of the first electrode 106 and the second
electrode 108 is a positively charged electrode. For purposes
discussed herein, either electrode 106, 108 may be positively
charged so long as the other electrode 106, 108 of the artificial
muscle 100 is negatively charged.
[0022] The first electrode 106 has a film-facing surface 126 and an
opposite inner surface 128. The first electrode 106 is positioned
against the first film layer 122, specifically, the first inner
surface 114 of the first film layer 122. In addition, the first
electrode 106 includes a first terminal 130 extending from the
first electrode 106 past an edge of the first film layer 122 such
that the first terminal 130 can be connected to a power supply to
actuate the first electrode 106. Specifically, the terminal is
coupled, either directly or in series, to a power supply and a
controller of an actuation system 400, as shown in FIG. 8.
Similarly, the second electrode 108 has a film-facing surface 148
and an opposite inner surface 150. The second electrode 108 is
positioned against the second film layer 124, specifically, the
second inner surface 116 of the second film layer 124. The second
electrode 108 includes a second terminal 152 extending from the
second electrode 108 past an edge of the second film layer 124 such
that the second terminal 152 can be connected to a power supply and
a controller of the actuation system 400 to actuate the second
electrode 108.
[0023] The first electrode 106 includes two or more tab portions
132 and two or more bridge portions 140. Each bridge portion 140 is
positioned between adjacent tab portions 132, interconnecting these
adjacent tab portions 132. Each tab portion 132 has a first end 134
extending radially from a center axis C of the first electrode 106
to an opposite second end 136 of the tab portion 132, where the
second end 136 defines a portion of an outer perimeter 138 of the
first electrode 106. Each bridge portion 140 has a first end 142
extending radially from the center axis C of the first electrode
106 to an opposite second end 144 of the bridge portion 140
defining another portion of the outer perimeter 138 of the first
electrode 106. Each tab portion 132 has a tab length L1 and each
bridge portion 140 has a bridge length L2 extending in a radial
direction from the center axis C of the first electrode 106. The
tab length L1 is a distance from the first end 134 to the second
end 136 of the tab portion 132 and the bridge length L2 is a
distance from the first end 142 to the second end 144 of the bridge
portion 140. The tab length L1 of each tab portion 132 is longer
than the bridge length L2 of each bridge portion 140. In some
embodiments, the bridge length L2 is 20% to 50% of the tab length
L1, such as 30% to 40% of the tab length L1.
[0024] In some embodiments, the two or more tab portions 132 are
arranged in one or more pairs of tab portions 132. Each pair of tab
portions 132 includes two tab portions 132 arranged diametrically
opposed to one another. In some embodiments, the first electrode
106 may include only two tab portions 132 positioned on opposite
sides or ends of the first electrode 106. In some embodiments, as
shown in FIGS. 1 and 2, the first electrode 106 includes four tab
portions 132 and four bridge portions 140 interconnecting adjacent
tab portions 132. In this embodiment, the four tab portion 132 are
arranged as two pairs of tab portions 132 diametrically opposed to
one another. Furthermore, as shown, the first terminal 130 extends
from the second end 136 of one of the tab portions 132 and is
integrally formed therewith.
[0025] Like the first electrode 106, the second electrode 108
includes at least a pair of tab portions 154 and two or more bridge
portions 162. Each bridge portion 162 is positioned between
adjacent tab portions 154, interconnecting these adjacent tab
portions 154. Each tab portion 154 has a first end 156 extending
radially from a center axis C of the second electrode 108 to an
opposite second end 158 of the tab portion 154, where the second
end 158 defines a portion of an outer perimeter 160 of the second
electrode 108. Due to the first electrode 106 and the second
electrode 108 being coaxial with one another, the center axis C of
the first electrode 106 and the second electrode 108 are the same.
Each bridge portion 162 has a first end 164 extending radially from
the center axis C of the second electrode to an opposite second end
166 of the bridge portion 162 defining another portion of the outer
perimeter 160 of the second electrode 108. Each tab portion 154 has
a tab length L3 and each bridge portion 162 has a bridge length L4
extending in a radial direction from the center axis C of the
second electrode 108. The tab length L3 is a distance from the
first end 156 to the second end 158 of the tab portion 154 and the
bridge length L4 is a distance from the first end 164 to the second
end 166 of the bridge portion 162. The tab length L3 is longer than
the bridge length L4 of each bridge portion 162. In some
embodiments, the bridge length L4 is 20% to 50% of the tab length
L3, such as 30% to 40% of the tab length L3.
[0026] In some embodiments, the two or more tab portions 154 are
arranged in one or more pairs of tab portions 154. Each pair of tab
portions 154 includes two tab portions 154 arranged diametrically
opposed to one another. In some embodiments, the second electrode
108 may include only two tab portions 154 positioned on opposite
sides or ends of the first electrode 106. In some embodiments, as
shown in FIGS. 1 and 2, the second electrode 108 includes four tab
portions 154 and four bridge portions 162 interconnecting adjacent
tab portions 154. In this embodiment, the four tab portions 154 are
arranged as two pairs of tab portions 154 diametrically opposed to
one another. Furthermore, as shown, the second terminal 152 extends
from the second end 158 of one of the tab portions 154 and is
integrally formed therewith.
[0027] Referring now to FIGS. 1-6, at least one of the first
electrode 106 and the second electrode 108 has a central opening
formed therein between the first end 134 of the tab portions 132
and the first end 142 of the bridge portions 140. In FIGS. 3 and 4,
the first electrode 106 has a central opening 146. However, it
should be understood that the first electrode 106 does not need to
include the central opening 146 when a central opening is provided
within the second electrode 108, as shown in FIGS. 5 and 6.
Alternatively, the second electrode 108 does not need to include
the central opening when the central opening 146 is provided within
the first electrode 106. Referring still to FIGS. 1-6, the first
electrical insulator layer 110 and the second electrical insulator
layer 112 have a geometry generally corresponding to the first
electrode 106 and the second electrode 108, respectively. Thus, the
first electrical insulator layer 110 and the second electrical
insulator layer 112 each have tab portions 170, 172 and bridge
portions 174, 176 corresponding to like portions on the first
electrode 106 and the second electrode 108. Further, the first
electrical insulator layer 110 and the second electrical insulator
layer 112 each have an outer perimeter 178, 180 corresponding to
the outer perimeter 138 of the first electrode 106 and the outer
perimeter 160 of the second electrode 108, respectively, when
positioned thereon.
[0028] It should be appreciated that, in some embodiments, the
first electrical insulator layer 110 and the second electrical
insulator layer 112 generally include the same structure and
composition. As such, in some embodiments, the first electrical
insulator layer 110 and the second electrical insulator layer 112
each include an adhesive surface 182, 184 and an opposite
non-sealable surface 186, 188, respectively. Thus, in some
embodiments, the first electrical insulator layer 110 and the
second electrical insulator layer 112 are each a polymer tape
adhered to the inner surface 128 of the first electrode 106 and the
inner surface 150 of the second electrode 108, respectively.
[0029] Referring now to FIGS. 2-6, the artificial muscle 100 is
shown in its assembled form with the first terminal 130 of the
first electrode 106 and the second terminal 152 of the second
electrode 108 extending past an outer perimeter of the housing 102,
i.e., the first film layer 122 and the second film layer 124. As
shown in FIG. 2, the second electrode 108 is stacked on top of the
first electrode 106 and, therefore, the first electrode 106, the
first film layer 122, and the second film layer 124 are not shown.
In its assembled form, the first electrode 106, the second
electrode 108, the first electrical insulator layer 110, and the
second electrical insulator layer 112 are sandwiched between the
first film layer 122 and the second film layer 124. The first film
layer 122 is partially sealed to the second film layer 124 at an
area surrounding the outer perimeter 138 of the first electrode 106
and the outer perimeter 160 of the second electrode 108. In some
embodiments, the first film layer 122 is heat-sealed to the second
film layer 124. Specifically, in some embodiments, the first film
layer 122 is sealed to the second film layer 124 to define a sealed
portion 190 surrounding the first electrode 106 and the second
electrode 108. The first film layer 122 and the second film layer
124 may be sealed in any suitable manner, such as using an
adhesive, heat sealing, or the like.
[0030] The first electrode 106, the second electrode 108, the first
electrical insulator layer 110, and the second electrical insulator
layer 112 provide a barrier that prevents the first film layer 122
from sealing to the second film layer 124 forming an unsealed
portion 192. The unsealed portion 192 of the housing 102 includes
an electrode region 194, in which the electrode pair 104 is
provided, and an expandable fluid region 196, which is surrounded
by the electrode region 194. The central openings 146, 168 of the
first electrode 106 and the second electrode 108 form the
expandable fluid region 196 and are arranged to be axially stacked
on one another. Although not shown, the housing 102 may be cut to
conform to the geometry of the electrode pair 104 and reduce the
size of the artificial muscle 100, namely, the size of the sealed
portion 190.
[0031] A dielectric fluid 198 is provided within the unsealed
portion 192 and flows freely between the first electrode 106 and
the second electrode 108. A dielectric fluid as used herein is a
medium or material that transmits electrical force without
conduction and as such has low electrical conductivity. Some
non-limiting example dielectric fluids include perfluoroalkanes,
transformer oils, and deionized water. It should be appreciated
that the dielectric fluid 198 may be injected into the unsealed
portion 192 of the artificial muscle 100 using a needle or other
suitable injection device.
[0032] Referring now to FIGS. 3 and 4, the artificial muscle 100 is
actuatable between a non-actuated state and an actuated state. In
the non-actuated state, as shown in FIG. 3, the first electrode 106
and the second electrode 108 are partially spaced apart from one
another proximate the central openings 146, 168 thereof and the
first end 134, 156 of the tab portions 132, 154. The second end
136, 158 of the tab portions 132, 154 remain in position relative
to one another due to the housing 102 being sealed at the outer
perimeter 138 of the first electrode 106 and the outer perimeter
160 of the second electrode 108. In the actuated state, as shown in
FIG. 4, the first electrode 106 and the second electrode 108 are
brought into contact with and oriented parallel to one another to
force the dielectric fluid 198 into the expandable fluid region
196. This causes the dielectric fluid 198 to flow through the
central openings 146, 168 of the first electrode 106 and the second
electrode 108 and inflate the expandable fluid region 196.
[0033] Referring now to FIG. 3, the artificial muscle 100 is shown
in the non-actuated state. The electrode pair 104 is provided
within the electrode region 194 of the unsealed portion 192 of the
housing 102. The central opening 146 of the first electrode 106 and
the central opening 168 of the second electrode 108 are coaxially
aligned within the expandable fluid region 196. In the non-actuated
state, the first electrode 106 and the second electrode 108 are
partially spaced apart from and non-parallel to one another. Due to
the first film layer 122 being sealed to the second film layer 124
around the electrode pair 104, the second end 136, 158 of the tab
portions 132, 154 are brought into contact with one another. Thus,
dielectric fluid 198 is provided between the first electrode 106
and the second electrode 108, thereby separating the first end 134,
156 of the tab portions 132, 154 proximate the expandable fluid
region 196. Stated another way, a distance between the first end
134 of the tab portion 132 of the first electrode 106 and the first
end 156 of the tab portion 154 of the second electrode 108 is
greater than a distance between the second end 136 of the tab
portion 132 of the first electrode 106 and the second end 158 of
the tab portion 154 of the second electrode 108. This results in
the electrode pair 104 zippering toward the expandable fluid region
196 when actuated. In some embodiments, the first electrode 106 and
the second electrode 108 may be flexible. Thus, as shown in FIG. 3,
the first electrode 106 and the second electrode 108 are convex
such that the second ends 136, 158 of the tab portions 132, 154
thereof may remain close to one another, but spaced apart from one
another proximate the central openings 146, 168. In the
non-actuated state, the expandable fluid region 196 has a first
height H1.
[0034] When actuated, as shown in FIG. 4, the first electrode 106
and the second electrode 108 zipper toward one another from the
second ends 144, 158 of the tab portions 132, 154 thereof, thereby
pushing the dielectric fluid 198 into the expandable fluid region
196. As shown, when in the actuated state, the first electrode 106
and the second electrode 108 are parallel to one another. In the
actuated state, the dielectric fluid 198 flows into the expandable
fluid region 196 to inflate the expandable fluid region 196. As
such, the first film layer 122 and the second film layer 124 expand
in opposite directions. In the actuated state, the expandable fluid
region 196 has a second height H2, which is greater than the first
height H1 of the expandable fluid region 196 when in the
non-actuated state. Although not shown, it should be noted that the
electrode pair 104 may be partially actuated to a position between
the non-actuated state and the actuated state. This would allow for
partial inflation of the expandable fluid region 196 and
adjustments when necessary.
[0035] In order to move the first electrode 106 and the second
electrode 108 toward one another, a voltage is applied by a power
supply. In some embodiments, a voltage of up to 10 kV may be
provided from the power supply to induce an electric field through
the dielectric fluid 198. The resulting attraction between the
first electrode 106 and the second electrode 108 pushes the
dielectric fluid 198 into the expandable fluid region 196. Pressure
from the dielectric fluid 198 within the expandable fluid region
196 causes the first film layer 122 and the first electrical
insulator layer 110 to deform in a first axial direction along the
center axis C of the first electrode 106 and causes the second film
layer 124 and the second electrical insulator layer 112 to deform
in an opposite second axial direction along the center axis C of
the second electrode 108. Once the voltage being supplied to the
first electrode 106 and the second electrode 108 is discontinued,
the first electrode 106 and the second electrode 108 return to
their initial, non-parallel position in the non-actuated state.
[0036] It should be appreciated that the present embodiments
disclosed herein, specifically, the tab portions 132, 154 with the
interconnecting bridge portions 174, 176, provide a number of
improvements over actuators, such as HASEL actuators, that do not
include the tab portions 132, 154. Embodiments of the artificial
muscle 100 including two pairs of tab portions 132, 154 on each of
the first electrode 106 and the second electrode 108, respectively,
reduces the overall mass and thickness of the artificial muscle
100, reduces the amount of voltage required during actuation, and
decreases the total volume of the artificial muscle 100 without
reducing the amount of resulting force after actuation as compared
to known HASEL actuators including donut-shaped electrodes having a
uniform, radially-extending width. More particularly, the tab
portions 132, 154 of the artificial muscle 100 provide zipping
fronts that result in increased actuation power by providing
localized and uniform hydraulic actuation of the artificial muscle
100 compared to HASEL actuators including donut-shaped electrodes.
Specifically, one pair of tab portions 132, 154 provides twice the
amount of actuator power per unit volume as compared to
donut-shaped HASEL actuators, while two pairs of tab portions 132,
154 provide four times the amount of actuator power per unit
volume. The bridge portions 174, 176 interconnecting the tab
portions 132, 154 also limit buckling of the tab portions 132, 154
by maintaining the distance between adjacent tab portions 132, 154
during actuation. Because the bridge portions 174, 176 are
integrally formed with the tab portions 132, 154, the bridge
portions 174, 176 also prevent leakage between the tab portions
132, 154 by eliminating attachment locations that provide an
increased risk of rupturing.
[0037] In operation, when the artificial muscle 100 is actuated,
expansion of the expandable fluid region 196 produces a force of 3
Newton-millimeters (N mm) per cubic centimeter (cm.sup.3) of
actuator volume or greater, such as 4 Nmm per cm.sup.3 or greater,
5 N mm per cm.sup.3 or greater, 6 Nmm per cm.sup.3 or greater, 7
Nmm per cm.sup.3 or greater, 8 N mm per cm.sup.3 or greater, or the
like. In one example, when the artificial muscle 100 is actuated by
a voltage of 9.5 kilovolts (kV), the artificial muscle 100 provides
a resulting force of 5 N. In another example, when the artificial
muscle 100 is actuated by a voltage of 10 kV the artificial muscle
100 provides 440% strain under a 500 gram load.
[0038] Moreover, the size of the first electrode 106 and the second
electrode 108 is proportional to the amount of displacement of the
dielectric fluid 198. Therefore, when greater displacement within
the expandable fluid region 196 is desired, the size of the
electrode pair 104 is increased relative to the size of the
expandable fluid region 196. It should be appreciated that the size
of the expandable fluid region 196 is defined by the central
openings 146, 168 in the first electrode 106 and the second
electrode 108. Thus, the degree of displacement within the
expandable fluid region 196 may alternatively, or in addition, be
controlled by increasing or reducing the size of the central
openings 146, 168.
[0039] As shown in FIGS. 5 and 6, another embodiment of an
artificial muscle 200 is illustrated. The artificial muscle 200 is
substantially similar to the artificial muscle 100. As such, like
structure is indicated with like reference numerals. However, as
shown, the first electrode 106 does not include a central opening.
Thus, only the second electrode 108 includes the central opening
168 formed therein. As shown in FIG. 5, the artificial muscle 200
is in the non-actuated state with the first electrode 106 being
planar and the second electrode 108 being convex relative to the
first electrode 106. In the non-actuated state, the expandable
fluid region 196 has a first height H3. In the actuated state, as
shown in FIG. 6, the expandable fluid region 196 has a second
height H4, which is greater than the first height H3. It should be
appreciated that by providing the central opening 168 only in the
second electrode 108 as opposed to both the first electrode 106 and
the second electrode 108, the total deformation may be formed on
one side of the artificial muscle 200. In addition, because the
total deformation is formed on only one side of the artificial
muscle 200, the second height H4 of the expandable fluid region 196
of the artificial muscle 200 extends further from a longitudinal
axis perpendicular to the central axis C of the artificial muscle
200 than the second height H2 of the expandable fluid region 196 of
the artificial muscle 100 when all other dimensions, orientations,
and volume of dielectric fluid are the same.
[0040] Referring now to FIG. 7, an artificial muscle assembly 300
is shown including a plurality of artificial muscles, such the
artificial muscle 100. However, it should be appreciated that a
plurality of artificial muscles 200 may similarly be arranged in a
stacked formation. Each artificial muscle 100 may be identical in
structure and arranged in a stack such that the expandable fluid
region 196 of each artificial muscle 100 overlies the expandable
fluid region 196 of an adjacent artificial muscle 100. The
terminals 130, 152 of each artificial muscle 100 are electrically
connected to one another such that the artificial muscles 100 may
be simultaneously actuated between the non-actuated state and the
actuated state. By arranging the artificial muscles 100 in a
stacked configuration, the total deformation of the artificial
muscle assembly 300 is the sum of the deformation within the
expandable fluid region 196 of each artificial muscle 100. As such,
the resulting degree of deformation from the artificial muscle
assembly 300 is greater than that which would be provided by the
artificial muscle 100 alone.
[0041] Referring now to FIG. 8, an actuation system 400 may be
provided for operating an artificial muscle or an artificial muscle
assembly, such as the artificial muscles 100, 200 or the artificial
muscle assembly 300 between the non-actuated state and the actuated
state. Thus, the actuation system 400 may include a controller 402,
an operating device 404, a power supply 406, and a communication
path 408. The various components of the actuation system 400 will
now be described.
[0042] The controller 402 includes a processor 410 and a
non-transitory electronic memory 412 to which various components
are communicatively coupled. In some embodiments, the processor 410
and the non-transitory electronic memory 412 and/or the other
components are included within a single device. In other
embodiments, the processor 410 and the non-transitory electronic
memory 412 and/or the other components may be distributed among
multiple devices that are communicatively coupled. The controller
402 includes non-transitory electronic memory 412 that stores a set
of machine-readable instructions. The processor 410 executes the
machine-readable instructions stored in the non-transitory
electronic memory 412. The non-transitory electronic memory 412 may
comprise RAM, ROM, flash memories, hard drives, or any device
capable of storing machine-readable instructions such that the
machine-readable instructions can be accessed by the processor 410.
Accordingly, the actuation system 400 described herein may be
implemented in any conventional computer programming language, as
pre-programmed hardware elements, or as a combination of hardware
and software components. The non-transitory electronic memory 412
may be implemented as one memory module or a plurality of memory
modules.
[0043] In some embodiments, the non-transitory electronic memory
412 includes instructions for executing the functions of the
actuation system 400. The instructions may include instructions for
operating the artificial muscles 100, 200 or the artificial muscle
assembly 300 based on a user command.
[0044] The processor 410 may be any device capable of executing
machine-readable instructions. For example, the processor 410 may
be an integrated circuit, a microchip, a computer, or any other
computing device. The non-transitory electronic memory 412 and the
processor 410 are coupled to the communication path 408 that
provides signal interconnectivity between various components and/or
modules of the actuation system 400. Accordingly, the communication
path 408 may communicatively couple any number of processors with
one another, and allow the modules coupled to the communication
path 408 to operate in a distributed computing environment.
Specifically, each of the modules may operate as a node that may
send and/or receive data. As used herein, the term U
communicatively couple& means that coupled components are
capable of exchanging data signals with one another such as, for
example, electrical signals via conductive medium, electromagnetic
signals via air, optical signals via optical waveguides, and the
like.
[0045] As schematically depicted in FIG. 8, the communication path
408 communicatively couples the processor 410 and the
non-transitory electronic memory 412 of the controller 402 with a
plurality of other components of the actuation system 400. For
example, the actuation system 400 depicted in FIG. 8 includes the
processor 410 and the non-transitory electronic memory 412
communicatively coupled with the operating device 404 and the power
supply 406.
[0046] The operating device 404 allows for a user to control
operation of the artificial muscles 100, 200 or the artificial
muscle assembly 300. In some embodiments, the operating device 404
may be a switch, toggle, button, or any combination of controls to
provide user operation. As a non-limiting example, a user may
actuate the artificial muscles 100, 200 or the artificial muscle
assembly 300 into the actuated state by activating controls of the
operating device 404 to a first position. While in the first
position, the artificial muscles 100, 200 or the artificial muscle
assembly 300 will remain in the actuated state. The user may switch
the artificial muscles 100, 200 or the artificial muscle assembly
300 into the non-actuated state by operating the controls of the
operating device 404 out of the first position and into a second
position.
[0047] The operating device 404 is coupled to the communication
path 408 such that the communication path 408 communicatively
couples the operating device 404 to other modules of the actuation
system 400. The operating device 404 may provide a user interface
for receiving user instructions as to a specific operating
configuration of the artificial muscles 100, 200 or the artificial
muscle assembly 300. In addition, user instructions may include
instructions to operate the artificial muscles 100, 200 or the
artificial muscle assembly 300 only at certain conditions.
[0048] The power supply 406 (e.g., battery) provides power to the
artificial muscles 100, 200 or the artificial muscle assembly 300.
In some embodiments, the power supply 406 is a rechargeable direct
current power source. It is to be understood that the power supply
406 may be a single power supply or battery for providing power to
the artificial muscle 100, 200 or the artificial muscle assembly
300. A power adapter (not shown) may be provided and electrically
coupled via a wiring harness or the like for providing power to the
artificial muscles 100, 200 or the artificial muscle assembly 300
via the power supply 406.
[0049] In some embodiments, the actuation system 400 also includes
a display device 414. The display device 414 is coupled to the
communication path 408 such that the communication path 408
communicatively couples the display device 414 to other modules of
the actuation system 400. The display device 414 may output a
notification in response to an actuation state of the artificial
muscles 100, 200 or the artificial muscle assembly 300 or
indication of a change in the actuation state of the artificial
muscles 100, 200 or the artificial muscle assembly 300. Moreover,
the display device 414 may be a touchscreen that, in addition to
providing optical information, detects the presence and location of
a tactile input upon a surface of or adjacent to the display device
414. Accordingly, the display device 414 may include the operating
device 404 and receive mechanical input directly upon the optical
output provided by the display device 414.
[0050] In some embodiments, the actuation system 400 includes
network interface hardware 416 for communicatively coupling the
actuation system 400 to a portable device 418 via a network 420.
The portable device 418 may include, without limitation, a
smartphone, a tablet, a personal media player, or any other
electric device that includes wireless communication functionality.
It is to be appreciated that, when provided, the portable device
418 may serve to provide user commands to the controller 402,
instead of the operating device 404. As such, a user may be able to
control or set a program for controlling the artificial muscles
100, 200 or the artificial muscle assembly 300 without utilizing
the controls of the operating device 404. Thus, the artificial
muscles 100, 200 or the artificial muscle assembly 300 may be
controlled remotely via the portable device 418 wirelessly
communicating with the controller 402 via the network 420.
[0051] From the above, it is to be appreciated that defined herein
is an artificial muscle for inflating or deforming a surface of an
object by selectively actuating the artificial muscle to raise and
lower a region thereof. This provides a low profile inflation
member that may operate on demand.
[0052] It is noted that the terms "substantially" and "about" may
be utilized herein to represent the inherent degree of uncertainty
that may be attributed to any quantitative comparison, value,
measurement, or other representation. These terms are also utilized
herein to represent the degree by which a quantitative
representation may vary from a stated reference without resulting
in a change in the basic function of the subject matter at
issue.
[0053] While particular embodiments have been illustrated and
described herein, it should be understood that various other
changes and modifications may be made without departing from the
scope of the claimed subject matter. Moreover, although various
aspects of the claimed subject matter have been described herein,
such aspects need not be utilized in combination. It is therefore
intended that the appended claims cover all such changes and
modifications that are within the scope of the claimed subject
matter.
* * * * *